The present invention relates to an endoscope apparatus and, more particularly, an endoscope apparatus having automatic observation-light control and automatic exposure functions.
An endoscope apparatus is generally designed to have observation and photographing functions and has been further provided with automatic light control and automatic exposure functions these days so as to enable observation and photographing to be carried out under optimum light and right exposure. In the case of conventional endoscope apparatus, however, a photoelectric element for receiving light reflected from an object is arranged in the endoscope while an exposure calculating circuit in the light supply unit, and a long signal line is employed to connect the photoelectric element to the exposure calculating circuit. When output signals of the photoelectric element pass through the signal line, therefore, noises are mixed with these output signals. This causes correctly-calculated value not to be obtained and the accuracy in automatic exposure to be lowered when the exposure calculating circuit calculates exposure on the basis of the output signals of the photoelectric element. Early-opened Japanese patent application No. Sho-55/121,879 discloses an endoscope apparatus in which the exposure calculating circuit is arranged in the endoscope camera so as to solve the drawback. In the case of this endoscope apparatus, however, the output signals of the photoelectric element are not transmitted to the light source unit, thus making it impossible to automatically control an observation light.